When images are captured by a camera, there are a number of factors that adversely affect the quality of the resulting image. One important factor is the sharpness of the image. There are several attributes of the imaging system that affect the sharpness of the image, such as the quality of the lens and the MTF (Modulation Transfer Function) of the image capture medium. But beyond these fundamental characteristics, there are other image-dependent factors that can seriously degrade the sharpness, and therefore the quality of the image. These factors include overall lens defocus (e.g., due to attempting to capture an image of an object that is too close to the camera), defocus of the main subject (e.g., due to the camera auto-focusing on the wrong object in the scene), insufficient depth-of-field to capture the range of important object distances, fogging of the lens element due to condensation of water vapor, and smearing due to motion of the camera and/or objects in the scene.
In conventional photography using photographic film, it is usually not possible to determine whether the captured image has acceptable sharpness until the film is processed and printed. With the advent of digital cameras, it is possible to review the image at the time of capture. In theory, this allows the photographer to assess the quality of the image, and if necessary, capture another image to correct image quality problems. However, the quality of the preview displays used on most digital cameras is insufficient to adequately evaluate the image quality in many cases. As a result, the photographer may not realize that the quality of an image is poor until the image has been printed or previewed at a later time on a high-resolution display. As a result, the photographer may miss any opportunity to capture an improved image, or may be dissatisfied that time/money was wasted in making a print of a poor quality image. Therefore, there is a need for a means to automatically assess the sharpness of an image at the time the image is captured.
Complete auto focus feature exists currently. But automatic capture of the focused image does not exist. The existing solutions are expensive since they require additional electromechanical controls. Such electromechanical parts increase the possibility of malfunction, thereby adversely affecting equipment size, weight, availability, mobility and increased maintenance costs. Additional electromechanical parts also increase the constraints on deployment of the equipment due to environmental factors such as dust, temperature and humidity. Manual image capture results in images that differ in focus levels and thus differing image characteristics such as focus and brightness.
The present invention addresses these problems and proposes a method and system for automatic detection and capturing focused image with uniform image characteristics across multiple images taken in a camera.